I definately agree about the suspensions. They are the newest technology going. The absolute best ergonomics. You can spend alot of money on the ol' 500 suspension and it would be hard to equal the plush ride of the new bikes. Also the 4 strokes have a great bottom end and really hook up on even the greasiest muddy conditions. That being said, they are very, very expensive to maintain and upgrade the engines. Before you buy a 4 stroke, look through an aftermarket parts catologue for heads, pipes, cams and valves. If that doesn't bother you, then maybe it would be worth looking into one. Then you have the kx 5 into a 250 or 450 mod. Its the cake and eat it too deal. There's alot of pro's and cons to it all, but its back to personal preference. New bikes are easier to find replacement parts, colored plastics, graphics or whatever seems hard to find for the ol' 2 strokes. 4 strokes used to be hard to start, but they are getting better all the time. (Especially, with electric start options) If money was not an issue, and did not have much bearing on which bike to ride, I would definately say the kx 500 motor on a new 450 chasis would be the "cream de la cream." Again BDI and Stewart pretty much covered the question, but I like adding to the convo.